The human brain is a remarkable thing. You can see, feel, touch and taste whatever you wan't to. I use to believe in ghost and demons, but i realized that the things i saw where just a mental effect left over after seeing almost every horror movie in the book, at a young age. My life has been a mess, and so is my mind, and i still see these apperations today some of them horribly realistic. Although my mind isnt quite right, it does have some advantages, i see things simpler than others, i get what most call deja vu almost every other day. Ive tried changing the outcomes but its folly seeming how it never changes even so. Some people may have high brain power and unknowingly be minipulating others into to thinking something is there, or may physically be moving objects, making sounds, or even producing the apperation entirely themselves. Don't fear the dead, fear eachother because we ourselves don't yet know what were capable of. This could also explain why the weakminded follow certain people.
Live every day as if already dead, that way you're not disappointed when you are.